ISTRAC Technical Assistant Electronics Paper 2019

ISTRAC Technical Assistant Electronics Paper 2019

A transponder is satellite equipment which
(a) Receives a signal from Earth station
(b) changes the frequency of the received signal
(c) retransmits the received signal
(d) does all of the above mentioned functions

An Operational Amplifier operated as a simple non inverting amplifier with a feedbac resistance 100 kilo ohms and an input resistance of 50 kilo ohms. Non inverting input is connected to ground. If -5 volts is applied to input, the output will
(a) -10 V
(b) 5 V
(c) 10 V
(d) -5 V

A 20 m antenna gives a certain uplink gain at frequencies of 4/6 GHz. For getting same gain in the 20/30 GHz band, antenna size required is metre.
(a) 100 Mtr
(b) 1 Mtr
(c) 4 Mtr
(d) 10 Mtr

RF amplifiers are used in radio receivers for
(a) To reject the image frequency Receiver
(b) To reject unwanted interference signal
(c) To boost the received signal at Receiver
(d) To remove superious signal from local oscillator

The material used in crystal oscillators
(a) Tank circuit
(b) Piezoelectric crystal
(c) R-C circuit
(d) None of the above

Noise factor of an ideal amplifier is ______
(a) 10 dB
(b) 1 dB
(c) 0.1 dB
(d) 0 dB